Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/30—Inkjet printing inks
  • C09D11/32—Inkjet printing inks characterised by colouring agents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/21—Ink jet for multi-colour printing
  • B41J2/2107—Ink jet for multi-colour printing characterised by the ink properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/17—Ink jet characterised by ink handling
  • B41J2/175—Ink supply systems ; Circuit parts therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/30—Inkjet printing inks
  • C09D11/40—Ink-sets specially adapted for multi-colour inkjet printing

Definitions

• the present invention relates to a recording ink used preferably for the inkjet recording and an ink cartridge, an ink record, an inkjet recording apparatus and an inkjet recording process which are provided using the recording ink.
• the inkjet printer according to the inkjet recording system can print in the plain paper, can be easily colorized, has a small size and the cost and running cost thereof is low, recently, it has been rapidly spread widely.
• the recording ink used for the inkjet recording system is required to have properties, such as a color tone, image density and spread for obtaining a high image quality, the dissolve stability of the colorant for obtaining the reliability, the water resistance and light-resistance of the ink for securing the keeping quality of the recorded image and the quick drying properties of the ink for obtaining the speedup of the printing and for satisfying these properties.
• JP-A Japanese Patent Application Laid-Open
• a pigment ink having a relative high viscosity is proposed. Particularly when with this ink, the printing is performed in a plain paper in high speed, the feathering and the color bleeding is rarely caused and a high quality image having an advantageous color tone can be obtained.
• this proposed pigment ink has a relative high glossiness as a pigment ink
• the printing is performed in a glossy paper
• this ink has such a disadvantage that this ink has yet a poorer glossiness in a glossy paper than that of a dye ink.
• the printing is performed using the dye ink and it is desired that the printing is performed using the pigment ink and dye ink properly alternately.
• the dye since the dye has a limit in the saturated solubility and affects adversely the show-through, it is not always easy to prepare a dye ink having the same high viscosity as that of the pigment ink. In the case where the printing is performed using the dye ink and pigment ink properly alternately, the segmentation of the colorant should be prevented.
• a dye ink which can be used alternately with a pigment ink having a specified pH is proposed in Japanese Patent Application Laid-Open (JP-A) No. 2002-60665.
• JP-A Japanese Patent Application Laid-Open
• an inkjet recording apparatus by which the printing using a pigment ink having a high viscosity can be performed (manufactured and sold by Ricoh Company, Ltd; trade name: Ricoh IPSiO G 707 and G 505) are developed.
• the pigment ink is printed; however it is neither disclosed nor indicated that using these recording apparatus, the dye ink is printed and the detail with respect to a dye ink which can be stably fed and printed is not yet studied.
• the dye ink is excellent in water-solubility
• the water-solubility of the dye ink is limited (cf. , the pigment ink which is a dispersion can be used irrespective the water-solubility thereof), so that in the case where a dye ink having a high density is used, when a volatile component of the ink is vaporized and the ink is dried up, the ink is crystallized and adheres solidly sometimes to other materials.
• the dye ink adheres solidly in the receiver for the blanc-delivery by which the dirt in the ink nozzle is blown out after the wiping during the cleaning procedure of the dirt in the inkjet head it is not easy to remove the dirt.
• the saturated water-solubility of the dye is limited and the image printed using the dye ink has a large show-through in comparison with the pigment ink, the selecting of a material by which the dye ink can be rendered to have a high viscosity is limited and the developing of a dye ink having a high viscosity has been not yet proceeded, so that the prompt development thereof is desired nowadays.
• the first object of the present invention is to provide a recording ink having excellent color developing properties and high delivery stability, by which not only an optimal combination of ink properties for the inkjet recording performed using a dye ink and a pigment ink properly alternately through one inkjet head can be obtained and the color saturation of the obtained image can be remarkably improved, but also the image having a high quality can be formed; and an ink cartridge, ink record, inkjet recording apparatus and inkjet recording process using the above-noted recording ink.
• the second object of the present invention is to provide a recording ink comprising a dye ink having a high viscosity, which is used for an inkjet recording apparatus comprising an inkjet head having a train of nozzles, a sub tank feeding the ink to the inkjet head, a negative-pressure generating unit which generates a negative pressure in the sub tank, an opening unit to the atmosphere by which the inside of the sub tank is opened to the atmosphere and a detecting unit by which the presence of the ink is detected by the difference in the electric resistance.
• the recording ink according to the present invention in the first aspect comprises a dye ink and a pigment ink which are used properly alternately through one inkjet head in an inkjet recording, wherein the dye ink and the pigment ink have respectively a viscosity at 25 ° C of 5 mPa- s or more and the difference between the viscosity of the dye ink and the viscosity of the pigment ink is 3 mPa- s or less.
• the above-noted recording ink has stable injection properties and by the above-noted recording ink, an image having a high image quality can be formed.
• a pigment ink comprising at least one of water, a pigment, a wetting agent, a Cs to On polyol compound and a glycol ether compound, and a surfactant and having a viscosity at 25 ° C of 5 mPa- s or more and a surface tension at 25 ° C of 40 mN/m or less, is used. Accordingly, an image having a little show-through and no spread can be obtained.
• a dye ink comprising water, a dye, a wetting agent, a viscosity-enhancing agent, a Cs to Cii polyol compound and a glycol ether compound and having a viscosity at 25 ° C of 5 mPa- s or more and a surface tension at 25 ° C of 40 mN/m or less, is used. Accordingly, a dye ink which not only is dried rapidly after the printing, has a little spread and bleeding and can exhibit glossy feeling in a glossy paper, but also is excellent in injection stability, can be obtained.
• the recording ink according to the present invention in the second aspect comprises a dye ink having a viscosity at 25 ° C of 5 mPa- s or more and a surface tension at 25 ° C of 40 mN/m or less, wherein the recording ink is used for an inkjet recording apparatus comprising an inkjet head having a train of nozzles, a sub tank feeding the ink to the inkjet head, a negative-pressure generating unit which generates a negative pressure in the sub tank, an opening unit to the atmosphere by which the inside of the sub tank is opened to the atmosphere and a detecting unit by which the presence of the ink is detected through the difference in the electric resistance.
• the recording ink is dried rapidly after the printing, has a little spread and bleeding and can exhibit glossy feeling in a glossy paper, but also the recording ink is excellent in injection stability and can form an image having a high image quality.
• the ink cartridge according to the present invention comprises the recording ink according to the above-noted first and second aspects of the present invention contained in a container and is preferably used for the printer of an inkjet recording system.
• the recording ink is excellent in color developing properties, has a high delivery stability, can improve remarkably color saturation and can form a high-quality image.
• the inkjet recording apparatus comprises at least an ink ejecting unit by which to the recording ink according to the first and second aspects of the present invention, an energy is applied and the recording ink is ejected for forming the image.
• the ink ejecting unit applies an energy to the recording ink according to the present invention and ejects the recording ink for forming the image. Therefore, by using the dye ink and the pigment ink properly alternately, the recording ink is excellent in color developing properties, has a high delivery stability, can improve remarkably color saturation and can form a high-quality image.
• the dye ink comprises an anti-forming agent, so that in the sub tank equipped with a detecting unit of the presence of the ink by which the presence of the ink is detected according to the difference in the electric resistance, the presence of the ink can be stably detected.
• a scraping unit which is a wiper or a cutter is provided, so that an adhered dye ink can be effectively scraped off.
• the inkjet recording process according to the present invention comprises at least the ejecting of a recording ink by which to the recording ink according to the first and second aspects of the present invention, an energy is applied and the recording ink is ejected for forming the image.
• an energy is applied and the recording is ejected, thereby forming the image. Accordingly, by using the dye ink and the pigment ink properly alternately, the recording ink is excellent in color developing properties, has a high delivery stability, can improve remarkably color saturation and can form a high-quality image.
• the ink record according to the present invention comprises the image formed on a recording medium using the recording ink according to the first and second aspects of the present invention.
• the recording ink is excellent in color developing properties, has high delivery stability, can improve remarkably color saturation and can hold a high-quality image in the recording medium.
• through one inkjet head means that in the case where the printing is performed using the dye ink and the pigment ink properly alternately in the inkjet recording apparatus, as the inkjet head, the same one inkjet head is used.
• the above-noted case includes cases where as another part of the inkjet recording apparatus, a part used specifically for the printing using the dye ink and a part used specifically for the printing using the pigment dye are alternately used, such as a case where a cartridge is specifically used for the printing using the dye ink and another cartridge is specifically used for the printing using the pigment ink.
• the case where a cartridge is specifically used for the printing using the dye ink and another cartridge is specifically used for the printing using the pigment ink include a case where after the printing using only the pigment ink, the same cartridge is filled with the dye ink and the printing is performed (a case where at this time, the cartridge is cleaned, is also included).
• the case represented by "through one inkjet head” includes all cases where the pigment ink and the dye ink are mixed even in a slight amount in the ink path (including also "in the waste ink trap").
• FIG. 1 is a graph showing an example of the titration curve for controlling the pH of a magenta pigment ink according to the present invention.
• FIG. 2 is a graph showing an example of the titration curve for controlling the pH of a yellow pigment ink according to the present invention.
• FIG. 3 is a graph showing an example of the relationship between the amount of the titer and pH.
• FIG. 4 is a view schematically showing an example of the ink cartridge according to the present invention.
• FIG. 5 is a view schematically showing an example of the ink cartridge in FIG. 4 contained in a casing according to the present invention.
• FIG. 6 is an explanatory view schematically showing an example of the inkjet recording apparatus according to the present invention.
• FIG. 7 is an explanatory view schematically showing an example of the inner structure of the inkjet recording 5 apparatus shown in FIG. 6.
• FIG. 8 is an expanded view schematically showing an example of the inkjet head according to the present invention.
• FIG. 9 is a view schematically showing an example of ⁇ o the train of nozzles for the inkjet head according to the present invention.
• FIG. 10 is an exploded perspective explanatory view schematically showing an example of the liquid feeding unit in the inkjet recording apparatus according to the present 15 invention.
• FIG. 11 is an expanded view of FIG. 10.
• FIG. 12 is an explanatory side view schematically showing an example of the sub tank.
• FIG. 13 A and B are longitudinal sectional views at 20 the A-A line shown in FIG. 12.
• FIG. 14 is a top view schematically showing an example of the maintaining unit for the inkjet printer according to the present invention.
• FIG. 15 is an explanatory view schematically showing
• FIG. 16 is a graph showing an example of the relationship between the amount of the wetting agent in the dye ink and the viscosity of the dye ink.
• FIG. 17 is a graph showing an example of the relationship between the amount of the nonionic surfactant in the dye ink and the viscosity of the dye ink.
• FIG. 18 is a graph showing an example of the relationship between the amount of the anionic surfactant ⁇ o in the dye ink and the viscosity of the dye ink.
• FIG. 19 is a graph showing an example of the relationship between the amount of the alginic acid in the dye ink and the viscosity of the dye ink.
• FIG. 20 is a graph showing an example of the particle 15 size distribution in a mixture of a dye ink and a pigment ink in Examples .
• the recording ink according to the present invention in the first aspect is used for the inkjet recording using a dye ink and a pigment ink properly alternately through one inkjet head, wherein the dye ink and the pigment ink have respectively an ink viscosity at 25 ° C of 5 mPa- s or more
• the difference between the viscosity of the dye ink and the viscosity of the pigment ink is 3 mPa- s or less.
• the recording ink according to the present invention in the second aspect is a recording ink used for an inkjet recording apparatus comprising an inkjet head having a train of nozzles, a sub tank feeding the ink to the inkjet head, a negative-pressure generating unit which generates a negative pressure in the sub tank, an opening unit to the atmosphere by which the inside of the sub tank is opened to the atmosphere and a detecting unit by which the presence of the ink is detected by the difference in the electric resistance and the recording ink is a dye ink having a viscosity at 25 ° C of 5 mPa- s or more and a surface tension at 25 ° C of 40 mN/m or less.
• the inkjet recording apparatus has a scraping unit which scrapes off an adhered ink into the receiver for the blanc-delivery and an aspect in which the scraping unit is any one of a wiper and a cutter, are preferred.
• the same dye ink as that in the recording ink according to the first aspect of the present invention can be used.
• the dye ink and the pigment ink have a viscosity at
• the difference between the viscosity of the dye ink and that of the pigment ink is 3 mPa- s or less, more preferably 1 mPa- s or less.
• the difference of viscosity is more than 3 mPa- s, it becomes difficult that under the same condition, both the dye ink and the pigment ink are caused to be stable particles.
• the viscosity of the dye ink is higher or lower than that of the pigment ink.
• the viscosity can be measured using, for example a rotating viscometer in the form of a conical plate.
• the difference (pH B - pH A) between the pH (pH A) of the pigment ink and the pH (pH B) of the dye ink is preferably -1 to 2.
• the pigment ink having a high pH was titrated with an acid having a proper concentration (which is adjusted according to the concentration of the ion-dissociated fraction), thereby obtaining a titration curve. More specifically, after the pH of 50 g of a magenta pigment ink in the below-noted Preparing Example 1 was elevated with sodium hydroxide, the magenta pigment ink was titrated with a 0.25 N HCI solution. The result of the titration is shown in Table 1.
• the magenta pigment ink has the ion dissociation constant at around a pH of 7.5 to 7.7 and has a pH buffer region at least in the pH region of from 6 to 9. In other words, at around pH 7.5, the half of the hydrophilic groups of the pigment dispersion is undissociated.
• the initial pH of the measured magenta pigment ink was 8.7 and it was confirmed that when pH of the ink becomes 8 or less, the number of particles having a large particle diameter becomes more. It was also confirmed that at pH of 6 or less (i.e., lower than the lower limit of the above-noted pH buffer region), all particles are fully precipitated. A cause thereof is that the magenta pigment ink has originally a high pigment concentration and a high viscosity.
• magenta pigment ink is attached to a paper, by a component of the paper, the magenta pigment ink is swiftly rendered to large particles (gelatinized), so that the large particles of the pigment ink is advantageous for the image having a high image quality
• magenta pigment ink is reacted with a compound lowering the pH of the reaction partner, a disadvantage is caused wherein large particles of the ink are rapidly precipitated in the ink path.
• the pH-buffer properties of the yellow pigment ink are similar to those of the magenta pigment ink (see FIG. 2). Also, the cyan pigment ink has similar pH-buffer properties.
• a dye ink having the ion dissociation constant at pH of 9.3 (e.g. , a yellow dye ink in Preparing Example 2 in Examples) has buffer properties until at least around pH of 7.5 and when a dye ink used properly alternately with a pigment ink, which has a pH which is lower than pH 8.7 of a pigment ink is mixed with the above-noted pigment ink having pH of 8.7, a proton is transferred to the pigment ink, so that the solubility of the pigment ink is lowered.
• the dye ink when the above-noted dye ink has a higher pH than that of the above-noted pigment ink, the dye ink does not precipitate the pigment ink in the mixing of these two inks, so that such a dye ink can be used properly alternately with such a pigment ink.
• the dye ink has a proper solubility in a lower pH side or higher pH side of the above-noted pH buffer region (, since the dye ink has a sulfon group which is ion-dissociated at a much lower pH).
• pH of the dye ink may not be much higher.
• the difference (pH B - pH A) between the pH (pH A) of the pigment ink and the pH (pH B) of the dye ink is preferably -1 to 2, more preferably 0 to 2.
• pH of the dye ink (pH B) is preferably higher than pH of the pigment ink (pH A).
• the ink is precipitated and can difficultly flow in the receiver for the blanc-delivery.
• the difference of pH is preferably 0 or more.
• the pigment ink according to the present invention has pH buffer properties in a pH region of 6 to 9 and in this pH region, the dispersion properties of the pigment ink are varied, it is necessary that pH of the dye ink is specified.
• the ink having pH buffer properties in a pH region of 6 to 9 and varying the dispersion properties thereof in the pH region has advantageous dispersion properties in an alkali region of pH and has such an effect that after the attaching of the ink to the paper surface, particles of the ink are swiftly agglomerated even in a neutral region of pH, so that the image quality becomes advantageous.
• the surface tension at 25 ° C of the pigment ink and of the dye ink respectively is preferably 40 mN/m or less, more preferably 35 mN/m or less.
• the surface tension can be measured using, for example a surface tension measuring apparatus (manufactured and sold by Kyowa Interface Science Co., Ltd.; trade name: CBVP-Z) according to the platinum plate method.
• the pigment ink by which no spread of the ink is caused and the printed image has a high density during printing using the pigment ink in the plain paper and which can be dried in high speed during printing using the pigment ink in the plain paper has preferably properties, such as an ink viscosity at 25 ° C of 5 mPa- s or more and a surface tension at 25 ° C of 40 mN/m or less.
• the printing was performed.
• a conventional dye ink for the inkjet printing has usually a viscosity of 5 mPa- s or less.
• a dye ink having a viscosity of 3 mPa- s was prepared and after the printing using the pigment ink, the experimental printing using the prepared dye ink instead of the pigment ink through the same inkjet head was performed. As the result of the experimental printing, the rendering to large particles was destabilized.
• the image quality With respect to the image quality, by the printing with the dye ink having the viscosity of 3 mPa- s using a driving wave pattern for injecting the pigment ink having the viscosity of 8 mPa- s, the amount of the used ink was too large, so that the density of the image in a glossy paper was too large and the image was wholly relative dark.
• the show-through (which means a phenomenon in which the image can be recognized from the reverse surface of the paper) may be caused at any rate more often than in the image printed using the pigment ink.
• the viscosity of the dye ink is enhanced to 5 mPa- s or more (which is depending on the type of the material enhancing the viscosity of the dye ink). It is considered that to the cause for lessening the occurrence of the show-through by using the dye ink having a high viscosity, both the decrease of the amount of the ink and the solidification of the ink in a near layer of the paper from the surface of the paper after the attaching of the ink to the surface of the paper, contribute.
• the using of the dye ink having such a low surface tension as 40 mN/m at 25 °C or less as the dye ink is based on the fact that by using the above-noted dye ink, in almost all recording media, the ink can swiftly penetrate into the media and be dried swiftly.
• wetting properties of the dye ink to the ink head member are improved and even if the dye ink is the dye ink having such a high viscosity as 5 mPa- s or more (at 25 °C), the frequency-number responsibility of the ink is improved, so that the delivery stability of the dye ink is remarkably improved.
• the pigment ink used properly alternately with the dye ink has a high viscosity and during the blanc delivery, the pigment ink is precipitated and set in the receiver for the blanc delivery.
• the dye ink having a low surface tension which can easily flow, the dye ink is not precipitated during the printing using the dye ink instead of the pigment ink.
• the using of the dye ink having such a high viscosity as 5 mPa- s or more has such an effect that by lessening a water content in the ink and enhancing the evaporation rate of water in the ink, the speed of the agglomeration of the dye in the surface of the paper is enhanced, so that the occurrence of the feathering is lessened.
• the forming stability after 5 minutes of the dye ink according to JIS K3362 is preferably less than 30 mm, more preferably 10 mm or less.
• the forming stability is 30 mm or more, the forming can difficultly disappear, so that the ink feeding action of the subtank is sometimes destabilized and the clogging of the ink path due to an air bubble is sometimes caused.
• the dye ink is not restricted so long as the dye ink has the viscosity at 25 ° C of 5 mPa- s or more and the surface tension at 25 ° C of 40 mN/m or less 5 and may be properly ⁇ elected depending on the application.
• the ink comprises at lest water, a dye, a wetting agent, a viscosity enhancing agent, any one of a Cs to C ⁇ polyol compound and a glycol ether compound and optionally other components.
• the dye examples include an acidic dye, a direct dye, a basic dye and a reactive dye.
• the acidic dye is not restricted and may be properly selected depending on the application. Examples of the
• acidic dye include a conventional dye for the food.
• Specific examples of the acidic dye include C . I. Acid Yellow 17, 23, 42, 44, 79 and 142; C . I. Acid Red 1, 8, 13, 14, 18, 26, 27, 35, 37, 42, 52, 82, 87, 89, 92, 97 , 106, 111 , 114, 115, 134, 186, 249, 254 and 289; C. I. Acid Blue 9, 29, 45, 92 and 249; C. I.
• the direct dye is not restricted and may be properly selected depending on the application.
• Examples of the direct dye include C. I. Direct Yellow 1 , 12, 24, 26, 33, 44,
• the basic dye is not restricted and may be properly selected depending on the application.
• Examples of the basic dye include C. I. Basic Yellow 1 , 2, 11 , 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 40, 41 , 45, 49, 51, 53, 63, 64, i o 65, 67, 70, 73, 77, 87 and 91; C. I. Basic Red 2, 12, 13, 14, 15, 18, 22, 23, 24, 27, 29, 35, 36, 38, 39, 46, 49, 51, 52, 54, 59, 68, 69, 70, 73, 78, 82, 102, 104, 109 and 112; C. I.
• the reactive dye is not restricted and may be properly selected depending on the application.
• Examples of the reactive dye include C. I. Reactive Black 3, 4, 7, 11, 12 and 17; C. I. Reactive Yellow 1, 5, 11, 13, 14, 20, 21, 22,
• the amount of the dye in the dye ink is preferably 5 4 % by mass or more, more preferably 4 % by mass to 15 % by mass, based on the mass of the dye ink.
• the amount is less than 4 % by mass, the image density is easily lowered and a dye ink having a high viscosity which is an object of the present invention can be difficultly obtained i o sometimes.
• the wetting agent water-soluble organic solvent having a high boiling point
• water-soluble organic solvent having a high boiling point water-soluble organic solvent having a high boiling point
• examples of the wetting agent include glycerine, 1,3-butanediol,
• the amount of the water-soluble organic solvent having a high boiling point in the dye ink is, when by increasing the amount of the wetting agent in the dye ink, the viscosity of the dye ink is enhanced, preferably 35 % by
• the viscosity of the dye ink is enhanced not by a viscosity enhancing agent.
• the amount is less than 35 % by mass, an objective dye ink having a high viscosity can be difficultly obtained and the 5 ink-injection is sometimes destabilized, so that the effect of enhancing the viscosity of the dye ink for the image (increasing the image density) can not be sometimes obtained.
• the amount is more than 50 % by mass, the show-through in the plain paper is i o more frequently caused.
• viscosity enhancing agent examples include a surfactant having a molecular weight of 300 to 1 ,000, a resin and emulsion having a molecular weight of 1,000 ore
• a compound having a water-soluble portion such as an ethylene oxide chain and a carboxyl group and a water-soluble compound having a thickening effect, such as an alginic acid compound.
• a surfactant an ethylene oxide chain and a carboxyl group
• a thickening effect such as an alginic acid compound.
• alginic acid a resin and an emulsion are used for enhancing the viscosity of the dye, these compounds are sometimes referred to as "a viscosity enhancing agent".
• surfactant examples include anionic surfactants or nonionic surfactants represented by the
• R 2 represents a C5 to Ci ⁇ alkyl group having a branched group and M represents any one of an alkali metal ion, a quaternary ammonium ion, a quaternary phosphonium ion and an alkanolamine ion,
• R 3 represents a hydrocarbon group, such as a C ⁇ to C14 alkyl group which may have a branched group and k is an integer of 5 to 20,
• R 6 represents a hydrocarbon group , such as a C ⁇ to Ci4 alkyl group and L, m, n and p are individually an 5 integer of 1 to 20,
• q and r are individually an integer of 0 to 40.
• the amount of the wetting agent is a not so large amount (i.e. , an usual amount, such as 15 % by mass i o to 30 % by mass), for enhancing the viscosity of the dye ink, the amount of the surfactant in the dye ink is preferably
• the using of the surfactant has such an advantage that when the printing is performed using a dye ink of which viscosity is enhanced by increasing the amount of the surfactant, the occurrence of the show-through of the printed image is suppressed.
• a similar effect to the effect of viscosity-enhancing of the surfactant can be obtained by incorporating a water-soluble polymer resin having a water-soluble portion, such as a carboxyl group and an ethylene oxide group in the dye ink.
• the alginic acid compound include an alginic acid and salts thereof.
• An alginic acid is a linear polysaccharide comprising two types of the uronic acid, such as ⁇ -(l-»4)-D-mannuronic acid (hereinafter referred to as "M”) and ⁇ -(l-»4)-L-glucuronic acid (hereinafter referred to as "G") and a block heteropolymer in which three blocks, such as (1) M block comprising only a M-M linkage, (2) G block comprising only a G-G linkage and (3) random block in which M and G are randomly arranged coexist, wherein the M/G ratio varies depending on a species of an algae comprising the alginic acid, a season and a portion of the algae.
• M ⁇ -(l-»4)-D-mannuronic acid
• G ⁇ -(l-»4)-L-glucuronic acid
• a carboxyl group which the above-noted M and G have can be easily ion-exchanged with various cations.
• the properties of the alginic acid are remarkably changed in a water system depending on the type of the cation which is bonded to a carboxyl group of the alginic acid.
• the cation include a sodium ion, a potassium ion, a calcium ion, an aluminum ion and an ammonium ion and due to such a cation, the 5 viscosity-enhancing and the gelation are caused.
• the alginic acid is utilized as a thickening agent, a gelatinizing agent, an emulsion stabilizer, a film forming agent, a shape retaining agent and a flocculating agent.
• the salts of the alginic acid include a potassium salt, sodium salt and ammonium salt thereof and among them, a sodium salt thereof is preferred.
• the alginic acid polymer is contained in a very large amount in an intercellular space of phaeophyceae, such as
• the alginic acid polymer can be obtained.
• alginic acid a commercially available product, such as an alginic acid having an ultra-low viscosity
• the amount of the alginic acid is preferably 4 % by mass or less, more preferably 1 to 3 % by mass, based on the mass of the dye ink.
• Examples of the Cs to C ⁇ polyol compound include 2-ethyl-l,3-hexanediol and 2,2,4-trimethyl-l ,3-pentanediol.
• Examples of the glycol ether compound include a polyalcohol alkyl ether, such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether and propylene glycol monoethyl ether; and a polyalcohol aryl ether, such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
• the amount of the Cs to Cii polyol compound or glycol ether compound is preferably 0.1 % by mass to 10.0 % by mass, based on the total mass of the recording ink.
• the anti-forming agent is not restricted and may be properly selected depending on the application.
• Preferred examples of the anti-forming agent include a silicone anti-forming agent, a polyether anti-forming agent and a fatty acid ester anti-forming agent. These anti-forming agents may be used individually or in combination. Among them, from the viewpoint of the excellence in the foam braking effect, a silicone anti-foaming agent is preferred.
• silicone anti-foaming agent examples include an oil silicone anti-foaming agent, a compound silicone anti-foaming agent, a self-emulsible silicone anti-foaming agent, an emulsion silicone anti-foaming agent and a modified silicone anti-foaming agent, such as an a ino-modified silicone anti-foaming agent, a carbinol-modified silicone anti-foaming agent, a methacryl-modified silicone anti-foaming agent, a polyether-modified silicone anti-foaming agent, an alkyl-modified silicone anti-foaming agent, a higher fatty acid ester-modified silicone anti-foaming agent and an alkylene oxide-modified silicone anti-foaming agent.
• the silicone anti-foaming agent considering the applying of the silicone anti-foaming agent to the recording ink which is a hydrophilic medium, the self-emulsible silicone anti-foaming agent and the
• the anti-foaming agent a commercially available product may be used.
• the commercially available product include a silicone anti-foaming agent (manufactured and sold by Shin-Etsu Chemical Co. , Ltd. ; trade name: KS-508, -531 and KM-72, -85), a silicone anti-foaming agent (manufactured and sold by Dow Corning Toray Silicone Co., Ltd.; trade name: Q2-3183A and SH5510), a silicone anti-foaming agent (manufactured and sold by 5 Nippon Unicar Company Limited; trade name: SAG 30) and a silicone anti-foaming agent (manufactured and sold by Asahi Denka Co. , Ltd.; trade name: Adekanate series).
• a silicone anti-foaming agent manufactured and sold by Shin-Etsu Chemical Co. , Ltd. ; trade name: KS-508, -531 and KM-72, -85
• the amount of the anti-foaming agent in the dye ink is not restricted and may be properly selected depending on i o the application.
• the amount is preferably 0.001 % by mass to 3 % by mass, more preferably 0.05 % by mass to 0.5 % by mass, based on the mass of the dye ink.
• the dye ink comprises the anti-foaming agent
• the dye ink is particularly excellent in the shelf stability
• the amount of the anti-foaming agent is less than 0.001 % by mass, the effect of the anti-foaming agent is sometimes unsatisfactory.
• the amount of the anti-foaming agent is more than 3 % by mass, the clogging of the ink is easily
• the pigment ink is not restricted so long as, as noted-above the pigment ink has a viscosity at 25 °C of 5
• the pigment ink comprises any one of water, a pigment, a wetting agent, a Cs to Cii polyol compound and a glycol ether compound, a surfactant and optionally other components.
• Preferred examples of the pigment include polymer fine particles comprising at least one of a water-insoluble colorant and a water-slight soluble colorant and a carbon black having at least one of hydrophillc groups in the surface thereof.
• the colorant may be dispersed in the emulsion.
• the colorant is not restricted so long as the colorant is water-insoluble or water-slight soluble and can be adsorbed on the polymer and may be properly selected depending on the application.
• water-insoluble or water-slight soluble means that the colorant cannot be dissolved in an amount of 10 parts by mass or more in 100 parts by mass of water at 20 ° C
• Being dissolved means that in an upper layer or lower layer of the water, the separation or sedimentation of the colorant is not visually observed.
• Examples of a polymer forming the above-noted emulsion include a vinyl polymer, a polyester polymer and a 5 polyurethane polymer.
• most preferred examples of the polymer include the vinyl polymer and the polyester polymer and specific preferred examples of the polymer include polymers disclosed in JP-A Nos. 2000-53897 and 2001-139849.
• Examples of the colorant as a black pigment include a carbon black.
• Examples of the colorant as a color pigment include a phthalocyanine blue, a phthalocyanine green, a quinacridone pigment, an anthraquinone pigment, a diazo pigment, a monoazo pigment, a pyranthrone pigment, a
• phthalocyanine blue examples include a copper phthalocyanine blue and a derivative thereof (e.g. , a pigment blue 15).
• quinacridone pigment examples include C.I. Pigment Orange 48 and
• Pigment Violet 19 and 42 examples include C.I. Pigment Red 43, 194 (perinone red),
• Examples of the perylene pigment include C.I. Pigment Red 123 (vermilion), 149 (scarlet), 179 (maroon) and 190 (red), C.I. Pigment Violet and C.I. Pigment Red 189 (yellow shade red) and 224.
• Examples of the (thio) indigoid include C.I. Pigment Red 86, 87, 88, 181 and 198 and C.I. Pigment Violet 36 and 38.
• Examples of the heterocyclic yellow include C.I. Pigment Yellow 117 and 138.
• Examples of the other proper coloring pigments include pigments described in the literature "The Color Index, the third edition (edited by The Society of Dyers and Colorists, 1982)". When the pigment is used as a colorant, for complementing or toning the color, the above-noted dye may be used in combination with the pigment.
• a self-dispersible color pigment which can be stably dispersed without using a dispersant having at least one hydrophilic group bonded to the surface of a carbon black directly or through another atom group, is preferably used. Accordingly, in comparison with a conventional ink, a dispersant for dispersing the carbon black in the ink is not necessary.
• the self-dispersible carbon black has preferably an ionity and preferred examples . thereof include that charged anionically and that charged cationically.
• anionic hydrophilic group which is bonded to the surface of the carbon black examples include -COOM, -SOsM, -POaHM, -PO3M2 -SO2NH2 and -SO2NHCOR, wherein M represents any one of a hydrogen atom, an alkali metal, an ammonium ion and an organic ammonium ion and R represents any one of a Ci to C12 alkyl group , a phenyl group which may have a substituent and a naphthyl group which may have a substituent.
• -COOM and -SO3M as the anionic hydrophilic group bonded to the surface of the carbon black in the color pigment, are preferred.
• Examples of "M” in the above noted hydrophilic group include, as an alkali metal, lithium, sodium and potassium and, as an organic ammonium, a mono or trimethyl ammonium, a mono or triethyl ammonium and a mono or trimethanol ammonium.
• Examples of the method for obtaining the above-noted anionically charged color pigment as a method for introducing -COONa group to the surface of the color pigment, include a method for subj ecting the color pigment to an oxidation using sodium hypochlorite, a method for sulfonating the color pigment and a method for reacting the color pigment with a diazonium salt.
• the wetting agent is not restricted and may be properly selected depending on the application.
• Examples of the wetting agent include the same wetting agents as those used for the dye ink.
• the amount of the wetting agent in the pigment ink is preferably 5 % by mass to 50 % by mass, more preferably 8 % by mass to 30 % by mass, based on the mass of the pigment ink.
• Cs to Cii Polyol Compound or Glycol Ether Compound - examples include the same Cs to C ⁇ polyol compound or glycol ether compound as those used for the dye ink.
• the surfactant is not restricted and may be properly selected depending on the application.
• examples of the surfactant include an amphoteric surfactant, an anionic surfactant, a cationic surfactant and a nonionic surfactant.
• amphoteric surfactant examples include alanine, dodecil di(aminoethyl) glycine, di(octylaminoethyl) glycine and N-alkyl-N,N-dimethyl ammonium betaine.
• anionic surfactant examples include a polyoxyethylene alkyl ether acetate salt, a dodecylbenzene sulfonate salt, a laurylate salt and a polyoxyethylene alkyl ether sulfonate salt.
• nonionic surfactant examples include a polyoxyethylene alkyl ether, a polyoxyethylene alkyl ester, a polyoxyethylene sorbitan fatty acid ester, a polyoxyethylene alkyl phenyl ether, a polyoxyethylene alkyl amine and a polyethylene alkyl amide.
• acetylene glycol surfactant examples include a 2,4,7,9-tetramethyl-5-decine-4,7-diol, 3,6-dimethyl-4-octine-3,6-diol and 3,5-dimethyl-l-hexine-3-ol (commercially available examples of the acetylene glycol surfactant include Surfynol 104, 82, 465, 485 and TG (manufactured and sold by Air Products and Chemicals, Inc. , U.S.A.)). Particularly, when Surfynol 465, 104 or TG is used for producing the pigment ink, the pigment ink exhibits an advantageous printing quality.
• the cationic surfactant examples include an amine salt surfactant, such as an alkyl amine salt, an amino alcohol fatty acid derivative, a polyamine fatty acid derivative and an imidazoline; and a quaternary ammonium salt surfactant, such as an alkyltrimethyl ammonium salt., a dialkyldimethyl ammonium salt, an alkyldimethylbenzyl ammonium salt, a pyrridinium salt, an alkylisoquinolinium salt and benzethonium chloride.
• an amine salt surfactant such as an alkyl amine salt, an amino alcohol fatty acid derivative, a polyamine fatty acid derivative and an imidazoline
• a quaternary ammonium salt surfactant such as an alkyltrimethyl ammonium salt., a dialkyldimethyl ammonium salt, an alkyldimethylbenzyl ammonium salt, a pyrridinium salt, an alkylisoquinolinium salt and
• the surfactant examples include also a surfactant containing fluorine.
• the surfactant containing fluorine is not restricted and may be properly selected depending on the application.
• Preferred examples of the surfactant containing fluorine include an anionic surfactant containing a fluoalkyl group and a cationic surfactant containing a fluoroalkyl group.
• the pigment ink may comprise an anti-forming agent and examples of the anti-forming agent include the same anti-forming agent as that used for the dye ink.
• Examples of the other components include an antiseptic and anti-fungus agent, a pH controlling agent, an anticorrosion agent, an antioxidant, an ultraviolet-absorbing agent, an oxygen-absorbing agent and a light stabilizer.
• antiseptic or anti-fungus agent examples include sodium dehydroacetate, sodium sorbate,
• l,2-benzisothiazoline-3-on is particularly preferred.
• the pH controlling agent is not restricted so long as the agent can control the pH of the ink to 7 or more without adversely affecting the produced ink and may be properly selected depending on the application.
• Examples of the pH controlling agent include an amine, such as diethanolamine and triethanolamine; a hydroxide of an alkali metal, such as lithium hydroxide, sodium hydroxide and potassium hydroxide; a hydroxide, such as ammonium hydroxide, quaternary ammonium hydroxide and quaternary phosphonium hydroxide; and a carbonate of an alkali metal, such as lithium carbonate, sodium carbonate and potassium carbonate.
• 2-amino-2-ethyl-l,3-propanediol is preferably used.
• This pH controlling agent is water-soluble and can be uniformly dissolved in an aqueous ink, so that this pH controlling agent does not affect adversely a colorant dispersed or dissolved in the aqueous ink. Further, this pH controlling agent has not only the function as a pH controlling agent, but also an extremely high effect for preventing the dissolution of the material for the inkjet head, when at least a part of the liquid space, fluid-resistance part, vibrating plate and nozzle member of the inkjet head is formed using a material comprising silicone or nickel, so that the extremely high effect for preventing the dissolution of the material for the inkjet head leads to a remarkable effect for the long-period reliability of the inkjet recording apparatus using an ink comprising this pH controlling agent (2-amino-2-ethyl-l,3-propanediol). Further, it was also clarified that this pH controlling agent has an extremely high effect for improving the delivery stability of the ink.
• anticorrosion agent examples include an acidic sulfite salt, sodium thiosulfate, ammonium thiodiglycolate, diisopropyl ammonium nitrite, pentaerythritol tetranitrate and dicyclohexylammonium nitrite.
• antioxidant agent examples include a phenol antioxidant (e.g. , a hindered phenol antioxidant), an amine antioxidant, a sulfur-containing antioxidant and a phosphor-containing antioxidant.
• phenol antioxidant including a hindered phenol antioxidant
• examples of the phenol antioxidant include butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl- ⁇ -(3 ,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2 ,2 '-methylenebis (4-ethyI-6-tert-butylphenol), 2,2 '-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), 3,9 ⁇ bis[2-[3-(3-t-butyl-4-hydroxy ⁇ 5-methylphenyl)- propyonyloxy]-l , l-dimeth ylethyl]-2 ,4,8 ,10- tetraoxyspiro[5.5]undecane,
• amine antioxidant examples include phenyl- ⁇ -naphthylamine, ⁇ -naphthylamine,
• sulfur-containing antioxidant examples include dilauryl-3,3'-thiodipropionate, distearyl-thiodipropionate, lauryl-stearyl-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl- ⁇ , ⁇ '-thiodipropionate, 2-mercapto-benzoimidazole and dilaurylsulfide.
• Examples of the phosphor-containing antioxidant include triphenyl phosphate, octadecyl phosphate, triisodecyl phophite, trilauryl-trithio phosphate and trinonylphenyl phosphate.
• the ultraviolet absorber examples include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylate ultraviolet absorber, a cyanoacrylate ultraviolet absorber and a nickel complex salt ultraviolet absorber.
• benzophenone ultraviolet absorber examples include 2-hydroxy-4-n-octoxybenzophenone,
• benzotriazole ultraviolet absorber examples include 2-(2'-hydroxy-5'-tert-octylphenyl) benzotriazole, 2-(2'-hydroxy-5'-tert-methylphenyl) benzotriazole,
• salicylate ultraviolet absorber examples include phenyl salicylate, p-tert-butylphenyl salicylate and p-octylphenyl salicylate.
• Examples of the cyanoacrylate ultraviolet absorber include ethyl-2-cyano-3,3'-diphenyl acrylate, methyl-2-cyano-3-methyl-3-(p-methoxyphenyl) acrylate and butyl-2-cyano-3-methyl-3-(p-methoxyphenyl) acrylate.
• nickel complex salt ultraviolet absorber examples include nickelbis (octylphenyl) sulfide, 2,2'-thiobis
• the pigment ink has pH of preferably 8 to 11.
• the dispersion of the pigment ink is sometimes destabilized.
• the liquid contacting properties of the pigment ink is sometimes impaired.
• the dye ink has pH of preferably 7 to 11.
• the pH of the dye ink is less than 7, the dispersion of the pigment ink is sometimes destabilized during the mixing of the dye ink with the pigment ink.
• pH of the dye ink is more than 11 , the liquid contacting properties of the dye ink is sometimes impaired.
• the color of the recording ink according to the present invention is not restricted and may be properly selected depending on the application.
• Examples of the color of the ink include yellow, cyan, magenta and black.
• the recording ink according to the present invention can be advantageously used in any one of inkjet heads of such types as a piezo type in which using a piezoelectricity element as a pressure generating unit applying the pressure to the ink in the ink path, a vibrating plate forming the wall of the ink path is deformed and the volume of the ink path is changed, so that the ink drop is delivered (see JP-A
• JP-A No. 02-51734 a thermal type in which using a heating element having a high electrical resistance, the ink is heated in the ink path and a bubble is generated (JP-A No. 61-59911); and a static charge type in which by the static power generated between a vibrating plate and an electrode, a vibrating plate is deformed and the volume of the ink path 5 is changed, so that the ink drop is delivered (see JP-A No. 06-71882).
• the recording ink according to the first and second aspects of the present invention can be preferably used in various fields as follows.
• the recording ink can be so i o preferably used in an image forming apparatus (e.g., a printer) of an inkjet recording system that by heating the recording ink together with a paper for the recording at 50 ° C to 200 ° C during, before or after the printing, the recording ink can be used for a printer of an apparatus
• the recording ink can be particularly preferably used for the following ink cartridge, ink record, inkjet recording apparatus and inkjet recording process according to the present invention.
• the ink cartridge according to the first and second aspects of the present invention comprises the recording ink according to the first and second aspects of the present invention which is encapsulated in a container and
• the container is not restricted and the form, structure, size and material thereof may be properly selected depending on the application.
• Preferred examples of the container include a container having at least an ink bag produced using an aluminum laminated film or a resin film.
• the capacity of the ink cartridge is preferably 15 g or more of an ink.
• the encapsulated amount of the ink is less than 15 g, in the case of the inkjet recording apparatus according to the present invention by which the printing is performed in a large amount of sheets of the paper, the frequency of changing the cartridge becomes high, so that the object and effect of the present invention cannot be obtained sometimes .
• the recording apparatus is improved for preventing the poor liquid contacting properties of the ink due to the preservation of the ink and the forming due to the air leak caused by the above-noted poor liquid contacting properties of the ink.
• FIG. 4 is a view schematically showing an example of the ink cartridge according to the present invention
• FIG. 5 is a view schematically showing an example of the ink cartridge in
• FIG. 4 contained in a casing according to the present invention.
• the ink cartridge 10, as shown in FIG. 4, is loaded
• the ink bag 41 is made of a packing material, such as an aluminum laminated-film having no gas-permeability.
• the ink bag 41 is usually, as shown in FIG. 5, encapsulated in the cartridge case 44 and is fitted in various inkjet recording apparatuses in an attachable and detachable
• the inkjet recording apparatus comprises at least an ink ejecting unit and other units selected properly depending on the
• the inkjet recording process according to the present invention comprises at least ejecting the ink and other steps selected properly depending on the necessity, such as
• the inkjet recording process according to the present invention can be preferably performed by the inkjet recording apparatus according the present invention and the ink ej ecting can be preferably performed by the ink 5 ej ecting unit. Further, the other steps can be preferably performed by the other units .
• the ink ejecting is the image-forming by applying a stimulation to the recording ink according to the first i o aspect of the present invention and by ejecting the recording ink and it is preferred that the image-forming is performed using the dye ink and the pigment ink properly alternately through one inkj et head.
• the ink ejecting unit is the image-forming unit by
• the ink ejecting unit is not restricted and may be selected depending on the application.
• Examples of the ink ejecting unit include various ink delivery heads . Among them, particularly an ink ejecting unit comprising an inkjet head (ink delivery head) having plural trains of nozzles and
• a sub tank holding a liquid fed from a tank for storing a liquid and feeding a liquid to the liquid drop delivering head is preferred.
• the sub tank comprises preferably a negative-pressure generating unit by which a negative pressure is generated in the sub tank, an opening unit to the atmosphere by which the inside of the sub tank is opened to the atmosphere and a detecting unit of the ink by which the presence of the ink is detected through the difference of the electrical resistance.
• the stimulation can be generated, for example by the stimulation generating unit.
• the stimulation is not restricted and may be properly selected depending on the application. Examples of the stimulation include a heat (temperature), a pressure, a vibration and a light. These stimulations may be used individually or in combination. Among them, the heat and the pressure are preferred.
• Examples of the stimulation generating unit include a heating apparatus, a pressurizing apparatus, a piezoelectricity element, a vibration generating apparatus, an ultrasonic oscillating machine and a light.
• Specific examples of the stimulation generating unit include a piezoelectricity actuator, such as a piezoelectricity element, a thermal actuator utilizing the phase change caused by the film boiling of the liquid which is generated using an electricity-heat exchange element, such as a heating element having a high electrical resistance, an actuator of a shape memory alloy utilizing the phase change of a metal due to the change of the temperature and a static actuator utilizing the static power.
• the aspect of ejecting the recording ink is not restricted and varies depending on the type of the stimulation as follows.
• the aspect is a method in which by applying a thermal energy corresponding to a recording signal to the recording ink in the recording head using, for example a thermal head, a bubble is generated in the recording ink by the applied thermal energy and by the pressure of the generated bubble, the recording ink is delivered and injected as a liquid drop through a nozzle pore of the recording head.
• an aspect is a method in which by applying a voltage to a piezoelectricity element installed at the so-called pressure space in the ink path of the recording head, the piezoelectricity element is made flex and the volume of the pressure space is decreased, so that the recording ink is delivered and injected as a liquid drop through a nozzle pore of the recording head.
• the inkjet recording apparatus comprises preferably also a scraping unit by which an adhered ink is scraped off into the receiver for the blanc-delivery.
• the scraping unit include a wiper and a cutter.
• the controlling unit is not restricted so long as the unit can control the action of the above-noted units and may be properly selected depending on the application.
• controlling unit examples include a sequencer and a computer.
• the inkjet recording apparatus shown in FIG. 6 comprises the main body 1, the paper feeding tray 2 attached to the main body 1 , the paper discharging tray 3 attached to the main body 1 in which the paper on which the image is recorded is stocked and the ink cartridge loading part 6.
• the operation part 7 comprising an operation key and a display instrument is disposed on the upper surface of the ink cartridge loading part 6, the operation part 7 comprising an operation key and a display instrument is disposed.
• the ink cartridge loading part 6 has the front cover 8 which can be opened and shut for attaching and detaching the ink cartridge 10.
• the carriage 13 is supported by the guide rod 11 and the stay 12 which are laid across the right and left side walls (not illustrated in FIGs.) of the main body in such a manner that the carriage 13 can be scanned flexibly in the main scanning direction and the carriage 13 is moved and scanned by a main scanning motor (not illustrated in FIGs.) in the direction indicated by the arrow in FIG.8.
• the recording head 14 comprising four heads for the inkjet recording which deliver respectively the recording ink drop of yellow (Y), cyan (C), magenta (M) and black (B) is fitted in such a manner that plural ink delivery outlets are oriented in the direction crossing the main scanning direction and the direction of the ink-drop delivery is downwards.
• a piezoelectricity actuator such as a piezoelectricity element
• a thermal actuator utilizing the phase change caused by the film boiling of the liquid which is generated using a electricity-heat exchange element, such as a heating element having a high electrical resistance
• an actuator of a shape memory alloy utilizing the phase change of a metal due to the change of the temperature
• a head equipped with a static actuator utilizing the static power as an energy generating unit for delivering the recording ink
• the carriage 13 is also equipped with the sub tank 15 of each color for feeding the ink of each color to the recording head 14.
• the recording ink according to the present invention is fed and supplemented from the ink cartridge 10 according to the present invention which is loaded in the ink cartridge loading part 6 through a feeding tube (not illustrated in FIGs.).
• the paper feeding part for feeding the paper 22 which is piled up on the paper loading part 21 (pressure plate) in the paper feeding tray 2 comprises the semicircular roller (the paper feeding roller 23) feeding the paper 22 one by one separately from the paper loading part 21 and the separating pad 24 made of a material having a large friction coefficient, wherein the separating pad 24 is biased to the paper feeding roller 23.
• the paper conveying part for conveying the paper 22 fed from the paper feeding part in the part beneath the recording head 14 comprises the conveying belt 31 for conveying the paper 22 by adsorbing the paper 22 statically, the counter roller 32 for conveying the paper 22 conveyed from the paper feeding part through the guide 25 by holding the paper 22 between the conveying belt 31 and the counter roller 32, the conveying guide 33 for changing the conveying direction of the paper 22 which is conveyed perpendicular upwards by 90 ° to convey the paper 22 onto the conveying belt 31 , the pressing member 34, the top-pressurizing roller 35 biased to the conveying belt 31 by the pressing member 34 and the charging roller 36 which is a charging unit for charging the surface of the conveying belt 31.
• the conveying belt 31 is an endless belt, is hung between the conveying roller 37 and the tension roller 38 and can be rotated in the direction of conveying the paper 22.
• the guide member 77 is disposed corresponding to the printing area by the recording head 14.
• the paper discharging part for discharging the paper 22 recorded by the recording head 14 comprises the peeling nail 51 for peeling the paper 22 from the conveying belt 31, the paper discharging roller 52 and the paper discharging roller 53, wherein the paper discharging tray 3 is disposed under the paper discharging roller 52.
• the both-surface paper feeding unit 61 is fitted in an attachable and detachable manner.
• the both-surface paper feeding unit 61 receives the paper 22 which is back-conveyed by the reverse rotating of the conveying belt 31 and reverses the conveying direction of the paper 22, thereby feeding the paper 22 between the counter roller 32 and the conveying belt 31.
• the manual paper feeding part 62 is installed above the both-surface paper feeding unit 61 .
• the paper 22 is fed one by one separately and upwards perpendicularly from the paper feeding part and conveyed between the conveying roller 31 and the counter roller 32 according to the guidance of the guide 25. Further, the top of the paper 22 is guided by the conveying guide 33, is pressed to the conveying belt
• the paper 22 is adsorbed statically to the conveying belt 31 charged by the charging roller 36 and
• the present invention can be also applied to a line inkjet recording apparatus equipped with a head in the form of a line.
• the recording head 14 (the general term for plural heads) consists of, as shown in FIG. 9, the liquid drop delivery head 14 a comprising the train of nozzles 14 yn which comprises many nozzles N delivering an ink drop of yellow (Y) and the train of nozzles 14 mn which comprises many nozzles N delivering an ink drop of magenta (M); and the liquid drop delivery head 14 b comprising the train of nozzles 14 en which comprises many nozzles N delivering an ink drop of cyan (C) and the train of nozzles 14 kn which comprises many nozzles N delivering an ink drop of black (Bk).
• the liquid drop delivery head 14 a comprising the train of nozzles 14 yn which comprises many nozzles N delivering an ink drop of yellow (Y) and the train of nozzles 14 mn which comprises many nozzles N delivering an ink drop of magenta (M); and the liquid drop delivery head 14 b comprising the train of nozzles 14 en which comprises many
• inks of the two colors among (Y), (M), (C) and (Bk) are fed to one head from the two individual sub tanks and inks of the other two colors among (Y), (M), (C) and (Bk) are fed to another head from the other two individual sub tanks (i.e., the recording head is equipped with two heads and four sub tanks) for the printing using inks of four colors; however, the printing may be performed also in such a manner that inks of the four colors are fed respectively to four individual heads having two trains of nozzles from four individual sub tanks (i.e., the recording head is equipped with four heads and four sub tanks) for the printing using inks of four colors.
• an inkjet printer manufactured and sold by Ricoh Company, Ltd.; trade name: IPSiO G707 having four heads which have two trains of nozzles was used.
• a piezoelectricity actuator such as a piezoelectricity element, a thermal actuator utilizing the phase change caused by the film boiling of the liquid which is generated using a electricity-heat exchange element, such as a heating element having a high electrical resistance, an actuator of a shape memory alloy utilizing the phase change of a metal due to the change of the temperature and a head equipped with a static actuator utilizing the static power as an energy generating unit for delivering the recording ink, can be used.
• a head equipped with a piezo electricity actuator (piezo electricity element) as an energy generating unit was used.
• the carriage 13 is equipped with four sub tanks 15 (more specifically 15 y, 15 m, 15 c and 15 k) as four liquid containers for feeding inks of four colors respectively to nozzles 14 yn, 14 mn, 14 en and 14 kn.
• the inks of four colors are respectively fed and supplemented from four main tanks (ink cartridges) 10
• FIG. 10 is an exploded perspective explanatory view schematically showing an example of the ink feeding apparatus
• FIG. 11 is a detail view of FIG. 10
• FIG. 12 is an explanatory side view schematically showing an example of the sub tank.
• the ink feeding apparatus consists of, as noted above, the sub tank 15 which is a liquid container feeding the ink to the recording heads 14 a and 14 b and which is equipped with the carriage 13 and the main tank (ink cartridge) 10 which feeds and supplements the ink to the sub tank through the feeding tube 16.
• One sub tank comprises the container main body (case main body) 101 forming the ink holding part 100 which holds the ink, the film member (flexible film member) 102 which is adhesive-bonded to the container main body 101 through adhesive-bonding or solvent-welding for sealing the opening of the ink holding part 100 (located in one surface of the sub tank 15) and the spring 103 which is a flexible member located between the case main body 101 and the film member 102 in the inside of the ink holding part 100 for biasing the film member 102 to the outside of the ink holding part 100.
• the film member 102 may be produced in a single-ply structure or, as shown in FIG.
• the film member 102 has a thickness of preferably 10 ⁇ m to 100 ⁇ m. When the thickness is less than 10 ⁇ m, a breakage due to the aging deterioration is easily caused sometimes. On the other hand, when the thickness is more than 100 ⁇ m, the flexibility of the film member 102 is lowered, so that the effective generation of the negative pressure in the film member 102 becomes difficult sometimes.
• the inflating part 102 a which is inflated to a convex form corresponding to the action of the spring 103 and the outer 5 surface thereof, the reinforcing member 104 is adhesive-bonded.
• the flexible member (here, the spring) 103 can be stably maintained.
• the convex part of the film member 102 can be easily formed.
• the ink introducing path 111 for supplementing the ink to the ink holding part 100 is formed and the connecting part 112 for connecting the ink
• the ink feeding path 114 is formed and between the ink
• the filter 115 is fitted.
• the airflow path 121 for purging air from the ink holding part 100 is formed.
• the airflow path 121 comprises the inlet flow path 122 5 which is opened to the ink holding part 100 and the successive flow path 123 (referred to as "orthogonal flow path") and the successive flow path 123 is connected communicative with the opening to the atmosphere 131 formed in the case 101 and with the accumulating part 126 i o which is located below the opening to the atmosphere 131.
• the valve for opening to the atmosphere 132 which alternates the closed state and opened-to the atmosphere state of the sub tank 15, is attached.
• the valve for opening to the atmosphere 132 is attached to the opening to the atmosphere 132
• valve 15 consists of the holder 133 and the valve seat 134, the ball 135 as the valve body and the valve spring 136 biasing the ball 135 to the valve seat 134 which are housed in the holder 133.
• two detecting electrodes 141 and 142 for detecting the state in which the amount of the ink in the sub tank 15 becomes the specified amount or less are fitted.
• FIG. 14 is a view schematically showing the view of the maintaining and recovering system 71 from a point over the maintaining and recovering system 71
• FIG. 15 is an explanatory view schematically showing the maintaining unit.
• the sub system 71 comprises the cap members 72 A and 72 B for capping the nozzle surfaces of the recording heads 14 a and 14 b and the wiper blade 73 for wiping the above-noted nozzle surfaces.
• the receiver for the blanc-delivery is arranged between the cap member 72 A and the wiper blade 73.
• the ink is delivered and the delivered ink flows to the waste liquid tank located under the receiver. Since at the part to which the ink is delivered, the ink is easily solidified, the wiper for scraping off the solidified ink is fitted. Particularly when the dye ink having a high viscosity is used, the wiper is effective for scraping off the solidified dye ink in the receiver for the blanc-delivery.
• scraping unit having a cutter is installed. Both the scraping unit having a wiper and scraping unit having a cutter for the pigment ink which are installed in the inkjet printer (manufactured and sold by
• the carriage lock 215 is biased upwards (in the direction of "locking") by a compression spring (not illustrated in FIGs. 14 and 15).
• the carriage lock 215 moves upwards and downwards by the carriage lock arm 217 contacted with the cam surface of the carriage lock cam 227. 5
• the caps 72 A and 72 B and the cap holder 212 A move upwards and downwards by the cap cams 222 A and 222 B.
• the wiper 73 moves upwards and downwards by the wiper cam 228.
• the wiper cleaner 218 is biased by a spring in the i o direction of departing from the wiper 73 and is operated toward the wiper by the wiper cleaner cam 218. While the wiper 73 falls between the wiper cleaner 218 and the receiver of the blanc-delivery, the ink attached to the wiper 73 is scraped off into the receiver for the blanc-delivery.
• a sensor (a photo interrupter / not illustrated in FIGs. 14 and 15) is fixed and the composition is so preset that when the cap is moved by the home position cam to the lowest position, the HP lever (not illustrated in FIGs. 14 and 15) is operated and the
• the 20 sensor is opened, so that the sensor detects the home positions of the motors (except the pump) (in other cases, the HP lever is not operated and the sensor is always closed. ).
• the cap is
• the carriage 25 moved upwards and downwards irrespective of the positions of the caps 72 A and 72B and the cap holders 212 A and 212 B (until the start of the moving, the detection of the position is not performed). After the cap has detected the home position of the cap (during the rising), the cap is 5 moved in a specified amount and to the lowest position. Thereafter, the carriage is moved right and left and after the carriage detects the position, the carriage returns to the position of capping, so that the carriage is capped.
• the inkjet recording apparatus and inkjet recording process according to the present invention can be applied to various recording according to the inkjet recording system, for example particularly preferably to the inkj et recording printer, the facsimile apparatus, the copy apparatus and a
• the record recorded by the inkjet recording apparatus and inkjet recording process according to the present invention is the ink record according to the present invention.
• the ink record according to the present invention comprises an image formed on a recording medium using the recording ink according to the present invention.
• the recording medium is not restricted and may be properly selected depending on the application.
• Examples of the recording medium include the normal paper, the glossy paper, the specified paper, the cloth, the film and the OHP sheet. These recording media may be used individually or in combination.
• the record has a high image quality and no spread of the ink, is excellent in the aging stability and can be preferably used in various applications , such as various materials in which letters are printed or images are recorded.
• 2-ethyl-l,3-hexanediol 2 % by mass of a nonionic surfactant (polyoxy alkylene derivative), 0.2 % by mass of a benzisothiazoline antiseptic and anti-fungus agent, 0.03 % by mass of a self-emulsifiable silicone anti-foaming agent (manufactured and sold by Shin-Etsu Chemical Co., Ltd. ; trade name: KM 72 F) (relative to 100 % by mass of the mass of the dye ink composition) and a proper amount of water were mixed and pH of the resultant mixture was adjusted with lithium hydroxide, thereby producing the dye ink of Production Example 8.
• a nonionic surfactant polyoxy alkylene derivative
• a benzisothiazoline antiseptic and anti-fungus agent 0.03 % by mass of a self-emulsifiable silicone anti-foaming agent (manufactured and sold by Shin-Etsu
• the relationship between the amounts of various wetting agents in the cyan dye inks obtained in Production Examples 1 to 4 and the viscosity of the cyan dye inks is shown in FIG. 16. From the result shown in FIG. 16, it is confirmed that the dye ink exhibiting preferred properties as the dye ink is the dye ink having a viscosity of 5 mPa- s to 10 mPa- s and the corresponding total amount of the wetting agent of 35 % by mass to 50 % by mass. When the amount of the wetting agent is too large, while the dye ink has a high viscosity, the show-through of . the image is frequently caused. On the other hand, when the amount of the wetting agent is too small, the dye ink has a low viscosity, so that the rendering of the dye ink to large particles is destabilized. 5 (Production Example 9)
• a magenta dye 1 (azo magenta dye), 1.25 % by mass of C.I. Acid Violet 102, 37.5 % by mass of i o diethylene glycol, 12.5 % by mass of glycerin, 2 % by mass of 2-ethyl-l,3-hexanediol, 2 % by mass of a nonionic surfactant (R-(OCH2CH2)nOH, wherein "R” represents a group of C13H2Y- and "n” is an integer of 3), 0.2 % by mass of a benzisothiazoline antiseptic and anti-fungus agent
• magenta dye 1 (azo magenta dye)
• the measurement of pH was performed using a pH meter (manufactured and sold by Toa Denpa Kogyo Co. , Ltd.; trade name: METER MODEL HM3A) at 23 ° C.
• METER MODEL HM3A METER MODEL HM3A
• the measurement of the viscosity was performed using a viscosity measuring apparatus (manufactured and sold by Toki Sangyo Co., Ltd. ; trade name: R 500 rotating viscometer) at 25 ° C.
• the measurement of the surface tension was performed using a surface tension measuring apparatus (manufactured and sold by Kyowa Interface Science Co. , Ltd. ; trade name: CBVP-Z) and a platinum plate at 25 ° C as a static surface tension.
• a surface tension measuring apparatus manufactured and sold by Kyowa Interface Science Co. , Ltd. ; trade name: CBVP-Z
• a platinum plate at 25 ° C as a static surface tension.
• the measurement of pH was performed using a pH meter (manufactured and sold by Toa Denpa Kogyo Co. ,
• the measurement of the viscosity was performed using a viscosity measuring apparatus (manufactured and sold by Toki Sangyo Co., Ltd.; trade name: R 500 rotating viscometer) at 25 ° C .
• the measurement of the viscosity was performed under the condition where a standard cone (having a cone angle of 1° 34' and a outer diameter R of 24 mm) was used and the rotation rate was a proper rotation rate in the range of from 40 rpm to 180 rpm.
• the measurement of the surface tension was performed using a surface tension measuring apparatus (manufactured and sold by Kyowa Interface Science Co . , Ltd.; trade name: CBVP-Z) and a platinum plate at 25 ° C as a static surface tension.
• CBVP-Z surface tension measuring apparatus
• FIG. 17 the relationship between the amount of the nonionic surfactant used in Production Example 12 and the viscosity of the dye ink produced in Production Example 12 is shown in FIG. 17 and the relationship between the amount of the anionic surfactant used in Production Example 13 and the viscosity of the dye ink produced in Production Example 13 is shown in FIG. 18. From the result shown in FIGs. 17 and 18, it is confirmed that when the amount of the surfactant is 7 % by mass or more, the produced dye ink has the viscosity of 5 mPa- s or more.
• the viscosity of the produced dye ink is rendered high, when the viscosity is more than 5 mPa- s or more (the amount of the surfactant is 7 % by mass or more), there is such an advantage that even if the image density in the surface of the paper is high, the show-through of the image does not become large.
• the image density in the plain paper becomes higher accompanying with increasing the amount of the surfactant and the viscosity of the dye ink as follows. The amount of the surfactant (the viscosity of the dye ink) was increased in such an order as in Production Example 16
• the image density was measured using a color spectrophoto-densitometer utilizing the reflection (manufactured and sold by X-Rite, Corporation, U.S.A.).
• a color spectrophoto-densitometer utilizing the reflection (manufactured and sold by X-Rite, Corporation, U.S.A.).
• 1,3-butanediol 5 % by mass of glycerin, 2 % by mass of
• 2-ethyl-l,3-hexanediol and 0.2 % by mass of a benzisothiazoline antiseptic and anti-fungus agent were mixed, thereby preparing the basic ink composition for the experiment of the viscosity controlling.
• a benzisothiazoline antiseptic and anti-fungus agent (relative to 100 % by mass of the mass of the dye ink composition) were mixed, thereby preparing the basic ink composition for the experiment of the viscosity controlling.
• 0 % by mass, 2 % by mass and 4 % by mass of an alginic acid (relative to 100 % by mass of the mass of the dye ink composition) were respectively 5 incorporated, thereby obtaining three types of the experimental ink composition for the experiment of the viscosity controlling.
• the used alginic acid is an alginic acid having the ratio D-mannuronic acid / L-glucuronic acid of about 0.47
• the amount of the alginic acid is preferably 4 % by mass or less. From the result shown in FIG. 19 , it is confirmed that by incorporating a combination of 2 % by mass to 4 % by mass of the alginic acid and 2 % by mass to 8 % by mass of the nonionic surfactant in the dye ink composition, the dye ink having a viscosity of 5 mPa- s to 10 mPa- s can be produced.
• the printing using the high-viscosity dye ink and the high-viscosity pigment ink properly alternately can be stably performed with a rare omission of ink delivery due to a nozzle trouble.
• a viscosity enhancing agent such as an alginic acid
• a high image quality having a high image density, a rare show-through and a rare feathering is incorporated in the dye ink composition.
• 2-ethyl-l,3-hexanediol 0.2 % by mass of a benzisothiazoline antiseptic and anti-fungus agent, 2 % by mass of an alginic acid, 6.5 % by mass of a nonionic surfactant (polyoxy alkylene derivative), 0.03 % by mass of a self-emulsifiable silicone anti-foaming agent (manufactured and sold by
• the measurement of pH was performed using a pH meter (manufactured and sold by Toa Denpa Kogyo Co . ,
• the measurement of the viscosity was performed using a viscosity measuring apparatus (manufactured and sold by Toki Sangyo Co. , Ltd. ; trade name: R 500 rotating viscometer) at 25 ° C.
• the measurement of the viscosity was performed under the condition where a standard cone (having a cone angle of 1° 34' and a outer diameter R of 24 mm) was used and the rotation rate was a proper rotation rate in the range of from 40 rpm to 180 rpm.
• the measurement of the surface tension was performed using a surface tension measuring apparatus (manufactured and sold by Kyowa Interface Science Co. , Ltd. ; trade name: CBVP-Z) and a platinum plate at 25 ° C as a static surface tension.
• CBVP-Z surface tension measuring apparatus
• the volume average particle diameter (D50%) was measured using a particle size distribution measuring apparatus (manufactured and sold by Nikkiso Co. , Ltd. ; trade name: Microtrack UP A) and found to be 93 nm.
• a particle size distribution measuring apparatus manufactured and sold by Nikkiso Co. , Ltd. ; trade name: Microtrack UP A
• a reddish-purple polymer fine particles dispersion was prepared in substantially the same manner as in preparation example 1, except that the copper phthalocyanine pigment was changed to the Pigment Yellow 74.
• the volume average particle diameter (D50%) was measured 5 using a particle size distribution measuring apparatus (manufactured and sold by Nikkiso Co. , Ltd. ; trade name: Microtrack UPA) and found to be 76 nm.
• Preparation Example 4 Preparing of Fine Particles Dispersion Comprising Carbon i o Black Subjected to Diazo Compound Treatment -
• a polymer fine particles dispersion comprising a phthalocyanine pigment (prepared in Preparation Example 1), 22 % by mass of 1,3-butanediol, 9.0 % by mass of glycerol, 2.2 % by mass of a nonionic surfactant (polyoxy alkylene derivative), 1.8 % by mass of 2-ethyl-l,3-hexanediol, 0.2 % by mass of a benzisothiazoline antiseptic and anti-fungus agent, 0.1 % by mass of a silicone anti-foaming agent (relative to 100 % by mass of the mass of the pigment ink composition) and a proper amount of an ion-exchanged water were mixed and stirred and the resultant mixture was subjected to the treatments, such as a pH adjusting treatment using an organic amine pH controlling agent for adjusting pH of the mixture to 9.5 and a filtration treatment using a membrane
• the viscosity and surface tension of the ink at 25 °C were measured and found to be, respectively 8.05 mPa- s and 29.4 i o mN/m.
• the measurement of the viscosity was performed using a viscosity measuring apparatus (manufactured and sold by Toki Sangyo Co., Ltd. ; trade name: R 500 rotating viscometer) at 25 °C.
• the measurement of the surface tension was performed using a surface tension measuring apparatus (manufactured and sold by Kyowa Interface Science Co. , Ltd. ; trade name: CBVP-Z) and a platinum plate at 25 ° C as a static surface tension.
• a nonionic surfactant polyoxy alkylene derivative
• 2-ethyl-l,3-hexanediol 1.5 % by mass of 2-ethyl-l,3-hexanediol, 0.07 % by mass of an antiseptic agent (sodium sorbate), 0.1 % by mass of a silicone anti-foaming agent (relative to 100 % by mass of the mass of the pigment ink composition) and a proper amount of an ion-exchanged water were mixed and stirred and the resultant mixture was subjected to a filtration treatment using a membrane filter having a pore size of 0.8 ⁇ m, thereby preparing the magenta pigment ink of Production Example 20.
• the viscosity and surface tension of the ink at 25 ° C were measured and found to be, respectively 7.95 mPa- s and 29.5 mN/m.
• the 5 viscosity and surface tension of the ink at 25 ° C were measured and found to be, respectively 8.02 mPa- s and 29.5 mN/m.
• composition 20 composition
• a proper amount of an ion-exchanged water were mixed and stirred and the resultant mixture was subjected to the treatments, such as a pH adjusting treatment using a 5 % by mass aqueous solution of lithium hydroxide and a filtration treatment using a membrane
• the viscosity and surface tension of the ink at 25 °C were measured and found to be, respectively 8.05 mPa- s and 30.2 mN/m.
• Each of the cyan pigment ink, magenta pigment ink, yellow pigment ink and black pigment ink which are produced in Production Example 20 has the surface tension and viscosity of the ink at 25 ° C of respectively 40 mN/m or less and about 8.05 mPa- s. Each of them is excellent in rapid dying properties, light resistance and water resistance, when they are used in the plain paper, and has a rare spread and a rare show-through.
• Example 1 to 16 and Comparative Examples 1 to 3 In Examples 1 to 16 and Comparative Examples 1 to 3, the dye ink and the pigment ink were respectively filled in an ink cartridge and another ink cartridge of an inkjet printer (manufactured and sold by Ricoh Company, Ltd.; trade name: IPSiO G707) according to a combination shown in the following Table 4.
• Table 4 Table 4
• Type* means, for example that in Example 1, as the pigment ink, the pigment ink produced in Pro. Ex. 20 (Production Example 20) was used and as the dye ink, the dye ink produced in Pro. Ex. 1 (Production Example 1) was used. ⁇ Evaluation>
• Example 1 to 16 and Comparative Examples 1 to 3 the printing using the pigment ink and the dye ink properly alternately through one head (with proviso that as the cartridge, a cartridge for the pigment ink and another cartridge for the dye ink were separately used) was performed by means of an inkjet printer (manufactured and sold by Ricoh Company, Ltd.; trade name: IPSiO G707) in a plain paper (Ricoh Type 6200) and in a glossy paper (Ricoh silky glossy paper) respectively.
• an inkjet printer manufactured and sold by Ricoh Company, Ltd.; trade name: IPSiO G707
• the inkjet printer manufactured and sold by Ricoh Company, Ltd; trade name: IPSiO G 707
• the presence of the ink was detected by measuring the electrical resistance using the above-noted electrodes 141 and 142 shown in FIG. 12 and when the absence of the ink was detected, the ink was supplemented in the sub tank.
• the misdetection was sometimes caused. It is estimated that the cause of the misdetection is a foam attached to the electrode and it is 5 also considered that the ink having a high viscosity is the cause for promoting the misdetection.
• the pigment ink was prepared as follows.
• nonionic surfactant polyoxy alkylene derivative
• 2-ethyl-l,3-hexanediol 1.8 % by mass of 2-ethyl-l,3-hexanediol
• 0.2 % by mass of a benzisothiazoline antiseptic and anti-fungus agent 0.1 % by mass of a silicone anti-foaming agent (relative to 100 % by mass of the mass of the pigment ink composition) and a
• the viscosity and surface tension of the ink at 25 °C were measured and found to be, respectively 11.4 mPa- s and 24.7 i o mN/m.
• Example 2 was injected instead of the pigment ink prepared in Comparative Example 4 and as the result, the ink could not be stably injected and the mist of the ink was frequently caused, so that a disadvantage was caused
• the pigment ink was prepared as follows. 10.0 % by mass (as a solid amount) of a polymer fine particles dispersion comprising a phthalocyanine pigment (prepared in Preparation Example 1), 13.5 % by mass of
• the viscosity and surface tension of the ink at 25 ° C were measured and found to be, respectively 4.8 mPa- s and 26 mN/m.
• the above-obtained pigment ink having a viscosity of 4.8 mPa- s and the dye ink produced in Production Example l l having a viscosity of 3 mPa- s were filled respectively in a cartridge and another cartridge of the inkjet printer (manufactured and sold by Ricoh Company, Ltd; trade name: IPSiO G 707).
• both the pigment ink and the dye ink could be stably injected; however, an image having a high quality and a lesser feathering as an advantage of an ink having a high viscosity could not be obtained.
• the dye ink needs to have a viscosity at 25 °C of 5 mPa- s or more.
• the dye ink comprising a viscosity enhancing agent, such as an alginic acid, a surfactant and a resin is preferred.
• a viscosity enhancing agent such as an alginic acid, a surfactant and a resin.
• the dye ink of Comparative Example 6 was prepared in substantially the same manner as in Production Example 2, except that 2-ethyl-l,3-hexanediol and the nonionic surfactant were not incorporated in the ink composition. With respect to the obtained dye ink, the viscosity and surface tension of the ink at 25 ° C were measured and found to be, respectively 7.15 mPa- s and 43.8 mN/m. ⁇ Evaluation>
• the above-obtained dye ink of Comparative Example 6 was filled in a cartridge of the inkjet printer (manufactured and sold by Ricoh Company, Ltd; trade name: IPSiO G 707) and the printing was performed in a plain paper (Ricoh Type 6200).
• IPSiO G 707 a plain paper
• the dye ink of Comparative Example 6 has a high surface tension, in the plain paper (Ricoh Type 6200), the drying rate of the ink was low and the feathering and spread of the ink were caused.
• the dye ink of Production Example 11 which has the viscosity and surface tension of the ink at 25 ° C of respectively 5 mPa- s or less and 40 mN/m or less was filled in a cartridge of the inkjet printer (manufactured and sold by Ricoh Company, Ltd; trade name: IPSiO G 707) and the printing was performed according to a driving wave pattern controlled for the printing using the pigment ink having the viscosity of 8 mPa- s. As the result, the printing could not be stably performed.
• Comparative Example 8 The pigment ink having a viscosity at 25 ° C of 5 mPa- s which was produced in Comparative Example 5 and the dye ink produced in Production Example 11 were filled respectively in a cartridge and another cartridge of the 5 inkjet printer (manufactured and sold by Ricoh Company, Ltd; trade name: IPSiO G 707).
• Microtrack UPA Microtrack UPA
• a reddish-purple polymer fine particles dispersion was prepared in substantially the same manner as in preparation example 1, except that the copper phthalocyanine pigment was changed to the Pigment Red
• the volume average particle diameter (D50%) was measured using a particle size distribution measuring apparatus (manufactured and sold by Nikkiso Co. , Ltd. ; trade name:
• Microtrack UPA Microtrack UPA
• the volume average particle diameter (D50%) was measured using a particle size distribution measuring apparatus (manufactured and sold by Nikkiso Co., Ltd. ; trade name: Microtrack UPA) and found to be 76 nm. 5 (Preparation Example 8)
• the obtained slurry was subjected to the treatments, such as a ten-times diluting treatment, a centrifuging treatment for removing bulky particles from the slurry, a pH adjusting treatment using diethanol amine
• the volume average particle diameter (D50%) was measured using a particle size distribution measuring apparatus 5 (manufactured and sold by Nikkiso Co. , Ltd.; trade name: Microtrack UPA) and found to be 99 nm.
• 1,3-butanediol 8.5 % by mass of glycerol, 2.1 % by mass of a nonionic surfactant (polyoxy alkylene derivative), 1.9 % by mass of 2-ethyl-l,3-hexanediol, 0.07 % by mass of an
• the measurement of the surface tension was performed using a surface tension measuring apparatus (manufactured and sold by Kyowa Interface Science Co., Ltd.; trade name: CBVP-Z) and a platinum plate at 25 ° C as a static surface tension.
• CBVP-Z surface tension measuring apparatus
• the measurement of the surface tension was performed using a surface tension measuring apparatus (manufactured and sold by Kyowa Interface Science Co. , Ltd. ; trade name: CBVP-Z) and a platinum plate at 25 ° C as a static surface tension.
• CBVP-Z surface tension measuring apparatus
• the yellow dye ink of Production Example 25 was produced in substantially the same manner as in Production 5 Example 22, except that in the ink composition, an organic amine pH controlling agent was not incorporated. (Production Example 26)
• the yellow dye ink of Production Example 26 was i o produced in substantially the same manner as in Production Example 22, except that the pH of the ink composition was adjusted to an objective pH with an acid (IN aqueous solution of hydrochloric acid).
• the yellow dye ink of Production Example 27 was produced by mixing the yellow dye ink of Production Example 25 and the yellow dye ink of Production Example 26 so that the pH of the yellow dye ink of Production 20 Example 27 becomes an objective pH.
• the dye ink has caused the show-through of the printed image more frequently than the pigment ink and was a little poorer than the pigment ink in the light resistance and the water resistance, when the printing was performed in the plain paper.
• a photograph image obtained using the dye ink had more glossy feeling than a photograph image obtained using the pigment ink.
• Example 22 or Production Example 25 has caused no problem.
• FIG. 20 shows an example of the mixing of 5 % by mass of the pigment ink with the dye ink, based on the
• an initial pH indicates pH of the dye ink before the mixing and another pH noted before the initial pH indicates pH of the mixed inks of the pigment ink and the dye ink.
• the presence of the ink is detected by measuring the electric resistance using the electrodes and according to the detecting of the absence of the ink, the ink is supplemented in the sub tank.
• the dye ink comprising no i o anti-foaming agent of Production Example 22
• the misdetection was often caused. It is assumed that the cause of the misdetection is an ink foam attached to the electrode.
• Production Example 22 has a 5-minutes foaming stability degree of about 30 mm or more and on the other hand, each
• 25 of the cyan dye ink, magenta dye ink and yellow dye ink of Production Example 23 has a 5-minutes foaming stability degree of 10 mm or less.
• the formed image has a low drying rate
• the recording ink according to the present invention is a recording ink having excellent color developing properties and high delivery stability which is used for the inkjet recording performed using a dye ink and a pigment ink properly alternately through one inkjet head and by which not only the color saturation of the obtained image can be remarkably improved, but also the image having a high quality can be formed and the recording ink can be preferably applied to an ink cartridge, an ink record, an inkjet recording apparatus and an inkjet recording process.
• the recording ink according to the present invention comprises a dye ink having a high viscosity, which is used for an inkjet apparatus comprising an inkjet head having a train of nozzles, a sub tank feeding the ink to the inkjet head, a negative-pressure generating unit which generates a negative pressure in the sub tank, an opening unit to the atmosphere by which the inside of the sub tank is opened to the atmosphere and a detecting unit by which the presence of the ink is detected by the difference in the electrical resistance and the recording ink can be preferably applied to an ink cartridge, an ink record, an inkjet recording apparatus and an inkjet recording process.

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